The present invention relates to methods and devices for destroying and removing unwanted materials such as calculi, deposits and tissues (for example, polyps, tumor cells) from body lumens, and more particularly to laser lithotripsy treatment of urinary stones.
Open surgical intervention was once the standard treatment for the removal of calculi or stones, especially when such calculi are deposited in a body lumen other than the bladder. But other less invasive techniques have emerged as safe and effective alternatives. Lithotripsy, the crushing of stones that develops in the body into fragments that are easier to remove, is one such technique. Lithotripsy devices have been developed which utilize electrohydraulic probes, ultrasonic probes, electromechanical impactors, or a pin driven by compressed air. These devices typically use percutaneous endoscopic techniques and are configured to be introduced into the body through small puncture sites to avoid open surgical intervention. Focused shock waves can also be delivered from an external source in a non-invasive procedure known as extracorporeal shock wave lithotripsy (ESWL).
Recently, lasers have been used as an alternative source of energy in lithotripsy, especially for the destruction of renal and bilary stones. Lasers are suited for minimally invasive lithotripsy because the diameter of the laser fiber is small and the aperture of the working channel can be minimized. An extensive review of the use of lasers for lithotripsy is provided in the book entitled xe2x80x9cLaser Lithotripsy,xe2x80x9d edited by R. Stein, Springer Verlag, 1988. A fiber optic that travels along the longitudinal axis of a rigid or flexible endoscope typically transmits the laser beam. Various types of laser lithotripsy systems with a variety of laser sources, including pulsed dye laser, alexandrite laser, neodymium laser and holmium laser, have been developed.
A common problem in intracorporeal lithotripsy treatment is the difficulty in restricting target movement. For example, when using pulsed lasers such as the holmium yttrium-aluminum-garnet (Ho:YAG) laser, higher frequency pulsation and higher energy in each pulse produce quicker fragmentation of the stone, but also produce significant stone mobility, which decreases treatment efficiency. Lower frequency of pulsation and lower pulse energy may result in less significant stone mobility, but the treatment time will be prolonged. Regardless of energy level of each emission, stones of smaller sizes present an inherent mobility problem. Incomplete lithotripsy treatment of smaller stones or debris can leave a nidus for future stone growth.
Another problem often encountered by a lithotripsy endoscopist involves the suction tube that is found in some endoscopes. Such a conduit is generally connected to a pump that produces a vacuum when in operation and clogging at distal ends by stones and their fragments has been widely reported. See, e.g. U.S. Pat. No. 4,146,019 to Bass et al. Severe clogging may necessitate repeated removal, cleaning and reinsertion of the endoscope during an operation.
An object of the present invention is thus to restrict the movement of targets of lithotripsy treatment, especially small stones and stone fragments. Another object of the invention is to remove stone fragments resulting from a lithotripsy treatment in a more complete and immediate manner. Yet another object of the invention is to solve the problem of clogging at the distal region of a suction conduit used in lithotripsy.
The present invention provides devices and related methods for the destruction and removal of unwanted materials such as calculi, deposits and tissues (e.g., polyps and tumor cells) from a patient""s body lumen. The invention achieves these objects by combining a suction conduit with a high-energy delivery system such that at least some of the high energy transmitted is directed to a region near the distal end of the suction conduit. For example, some of the energy can be directed inside, outside, at the face of the tip or a combination thereof. As a result, the energy destroys materials stuck at the distal end of the suction conduit and provides the user with a suction device that is equipped with a non-clogging tip.
The devices of the invention comprises a suction conduit connected to a pump for suction and a second conduit connected to an energy source for transmitting high energy. Once the suction conduit is in operation, it keeps stones or stone fragments near its tip, stabilizing the movement of the stone. The second conduit is designed to direct a portion of the high energy into, across, and/or outside of the distal end of the suction conduit and thus onto the stones or stone fragments. The energy fragments, pulverizes or erodes stones, including those caught by the force of suction onto the tip of the suction conduit, into smaller parts or dusts, and the suction conduit can instantaneously evacuate the stone debris. For example, in a preferred embodiment where Ho:YAG laser is used as the energy source, the laser energy continues to break down fragments that are still too large to enter the suction conduit while knocking them off the suction tip temporarily thus preventing clogging of the tip. A portion of the energy may also be directed into a portion of the lumen of the suction conduit, thereby preventing clogging that would have occurred after debris entered the conduit.
The devices and methods of the invention take full advantage of the suction force in removing debris instantaneously from the site of the treatment, allowing a more complete and speedy treatment. Also, by directing a high energy towards the distal region of the suction conduit, the devices point the energy into a region where targets are accumulated and relatively immobilized by the suction. The devices and methods thus offer enhanced treatment efficiency by permitting a more thorough removal of debris and by avoiding operational difficulties associated with a clogged suction conduit.
In one aspect, the devices of the invention can also be equipped with structures such as barriers or shields in the distal region of the suction conduit to help block large particles. In another aspect, the devices of the invention use multiple energy conduits bundled or dispersed in or around the wall of the suction conduit. Yet in another aspect, the devices use multiple conduits bearing indicia or marking that permit their identification during a procedure. In still another aspect, the devices of the invention direct energy towards the distal region of the first suction conduit with or without a separate optical apparatus such as mirrors, lenses, prisms for example.
The devices and methods of the invention can be used for the removal of stones and calcifications throughout the body. First, the device is inserted into the body lumen of a patient and the distal end of the suction conduit is positioned near a stone. Then, a high energy is transmitted by the energy conduits and directed to the distal region of the suction conduit, thereby breaking up stones stuck at the distal region and removing its fragments through suction.
The devices can also be utilized for the removal of soft tissue such as polyps or tumor cells. For example, the device is first inserted into the body lumen of a patient and the distal end of the suction conduit is positioned near the tissue to be removed. Then, a high energy is transmitted by the energy conduits and directed to the distal region of the suction conduit and thereby shearing off the tissue and removing it through suction. Additionally, the devices can be used for orthopedic applications and endoscopic applications such as arthroscopy and endoscopic retrograde cholangio-pancreatiography (ERCP).
The foregoing and other objects, aspects, features, and advantages of the invention will become more apparent from the following description and from the claims.